1. Field of the Invention
The field of this invention lies within the art of lighted displays, indicators and readouts. More particularly, it lies within the fiber optic or light pipe readout art wherein an incandescent bulb is utilized to transmit light on a logically designated basis through a plurality of light pipes or fiber optic elements to create a desired display within such areas as industrial and aircraft displays.
2. The Prior Art
The prior art related to readouts and indicators for displays used in aircraft, industrial panels and general readouts often incorporates incandescent lighting or light emitting diodes. When incandescent lamps are utilized, it is oftentimes in conjunction with certain fiber optic or light pipe combinations. In particular, a lamp or plurality of lamps will be utilized with respect to a number of fiber optic or light pipe elements that terminate on the face of the readout or display. This is particularly common in aircraft fiber optic readouts.
In such fiber optic readouts, the incandescent lamp or light source and the fiber optic light pipe transmit the light directly to the display face to provide the net result of a minimal amount of lost light. The displays are created by lighting various combinations of lamps connected to the dot patterns or readouts at their terminal points by virtue of the connectors of the lamp being connected to a particular logic network. In this manner, improved standards of legibility and brightness for such displays as avionic displays, and other control panels, whether they be industrial or otherwise, are created. The end result is to create displays readable in extremes of ambient lighting conditions.
The readouts generally have a heat sink in order to drain the heat generated by the incandescent lamps. By draining the heat through a heat sink, the net result is to create a situation wherein the lamp can be lit from high voltages to low voltages, depending upon the amount of lighting output that is required.
The lamps are interfaced with their fiber optical tubes or light pipes which terminate at the surface which provides the readout. This surface is exposed to ambient lighting, and as a consequence, both the light created by the incandescent lamps and the ambient lighting must be balanced and often conflict with each other in order to create a proper display.
One of the main problems of the prior art is that when a very low level lighting condition is to be utilized, the incandescent filaments do not provide the uniformity of coverage and light output. This is particularly serious in low level lighting conditions where a particular output is required at a low level, and it must be uniform.
A second problem is that the diffusers of the prior art allow for an introduction of ambient light into the light pipes which then allows the light to scatter and be displayed in a spurious manner, so that the appearance of a false readout or display is provided. In other words, the outside lighting is reflected backwardly after it passes into the display through the light pipes and creates a spurious reading of the given display, thereby causing confusion.
This invention overcomes the foregoing two deficiencies of low voltage level lighting problems and spurious displays. The diffuser and its characteristics allow for ambient light to be absorbed and readily diffused to prevent spurious lighting displays on the face of the display. The diffuser of this invention thereby serves the multi purpose of providing proper low level lighting at low voltages, while at the same time preventing ambient light from causing spurious readings.